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    Re: 18 june 2013 lunar distance
    From: Frank Reed
    Date: 2013 Jul 5, 16:40 -0700

    Hi Brad,

    Yes, indeed. The data are all out there, and it's a solvable addition to the lunar problem --but again, this is at the 1-2 arcsecond level, so nothing big.

    As recently as ten years ago, there was no proper "DEM" (digital elevation model" for the Moon, but now there are several highly detailed models thanks to the Japanese Kaguya mission and the US Lunar Reconnaissance Orbiter (and maybe that Chinese orbiter, too). And the libration issue is relatively simple. All the pieces are in place. I've considered adding this to software for some years. It's down around the middle of my "to do" list --in the category of "things that won't make any money, might be somewhat fun (but not much), could easily be duplicated by others, and will only add very slightly to the accurate solution of a standard problem." But I have worked on it. I was looking at my last iteration of this just two days ago while digging through some old files. I estimate that I could create the additional software for this and add it my standard lunar clearing tools in about two days. Given my usual estimate multiplier, that's really about a ten-day project. I don't see much chance that I will get around to it this year. Unless you would like to pay me... :) Ha!

    As for making his-his-history, perhaps you have not heard of "Reed's Vertical Circle" method for clearing lunars? A surprisingly large number of lunars can be cleared with no trig, no log tables whatsoever. It's the greatest thing since sliced bread! (again, Ha!) Or if you have heard of it, then my time machine experiments have succeeded and Nevil Maskelyne recommended it as the easiest method for clearing lunars back in the first edition of the Tables Requisite in 1767.

    Speaking of digging around in files, I was looking over Aldo Vitagliano's "SOLEX" software on my computer and downloaded a more recent version from his web site. While there, I learned that he is publicizing an astronomical event that his software helps to calculate accurately. It's an AMAZING astronomical event, and you and I, and anyone else in the northeast US and Canada, are very close to front-row seats. On March 20, 2014, at about 1:05 in the morning EST, the faint asteroid Erigone is going to occult the bright star Regulus as seen along a narrow path, about forty miles wide that just happens to pass right over New York City. Since Erigone will be twelfth magnitude, bright Regulus will vanish, blink right out of the sky!, for about a dozen seconds. A minute later the shadow will pass over Syracuse before heading up across Ontario. No one seems to have noticed that the track also passes directly over Bermuda about two minutes before reaching NYC. This will be a spectacle for casual observers even in brightly-lit cities, and also great for amateur astronomers. Careful photometric timing, which is relatively easy with a bright star like Regulus, will yield an extremely accurate profile of the asteroid and will probably also detect any moons of Erigone. Pray for clear skies!


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